Interpretive Summary: The ability to separate females from male insects during rearing is a critical need for successful biologically-based control programs for tephritid insect pests using the Sterile Insect Technique (SIT). However, sexing systems at the embryonic stage have, thus far, only been developed for the Mediterranean fruit fly. To develop new and effective sexing systems for other tephritid species, scientists at the USDA/Agriculture Research Service, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, have taken advantage of the fortuitous integration of fluorescent protein-marked transgene vectors into the Y chromosome of the Caribbean fruit fly, Anastrepha suspensa. This resulted in several strains having male-specific expression of the fluorescent protein, one of which expresses during the embryonic stage. Such fluorescent male embryos can be detected by automated systems that separate them from the non-fluorescent females, allowing sexing early in development. This provides a system applicable to most tephritid flies controlled by SIT for simple and efficient genetic sexing for improved biologically-based control.

Technical Abstract:
Insect pest control programs incorporating the sterile insect technique (SIT) rely on the mass production and release of sterilized insects to reduce the wild-type population through infertile matings. Most effective programs release only males to avoid any crop damage caused by female fruit flies or transmission of disease by female mosquitoes. Therefore, the females have to be eliminated, preferably in an early developmental stage, during mass rearing. Different systems and techniques have been created for the sex separation of a few insect species. One of these is the transgenic sex-specific fluorescent protein marking of the insects with automated fluorescent-based sorting of the individuals to achieve sex separation. Here we describe the Y-linked integration of fluorescent markers driven by the widely active Drosophila melanogaster polyubiquitin promoter in the Caribfly, Anastrepha suspensa Anastrepha suspensa . Four strains with Y-linked integrations were established with one line expressing the DsRed fluorescent protein marker during embryogenesis. This line now has the possibility for use with automated sex separation in rearing, and the same transgene markers could be used in other insects for similar applications.